import io.reactivex.Observable;

public class C23a {
    public static void main(String[] args) {
        Observable.just(1, 1, 1, 2, 2, 3, 3, 2, 1, 1)
                  .distinctUntilChanged()
                  .subscribe(i -> System.out.println("RECEIVED: " + i));
    }

}
//EOP
